Oel-mkcible



OIL-IVIISCIBLE, WATER INSOLUBLE SOAP COMPLEXES 14 Claims. (Cl. 25235) This invention has to do generally with the manufacture of soaps and grease-contained soaps of polycarboxylic acids, and has for its general object to provide new polyvalent metal soap compositions which have such miscibility and gel compatibility with hydrocarbon oils that will permit the formation of uniform and stable grease compositions possessing to full degree the beneficial properties known to be imparted by the water insoluble polyvalent or monovalent metal soaps of polycarboxylic acids.

It is known that these soaps in themselves are not oil soluble or compatible for purposes of grease making, to the extent that they may be used alone as the soap component of a good quality grease. As one means of rendering, in a sense, water insoluble polyvalent polycarboxylic acid soaps compatible with an oil, it has been proposed to form soap complexes of dicarboxylic acid and monocarboxylic acid by coformation of the soap component from mixtures of the acids (it being recognized that the dimer soap cannot effectively be introduced and the desired grease properties created and maintained simply by using a mixture of the polyvalent metal dimer and monomer soaps). Specifically, it has been proposed to precipitate together mixed dicarboxylic and monocarboxylic acids by a polyvalent metal such as aluminum, to produce a soap complex in which the acid radicals are cross-linked and thus chemically compounded.

The present invention also contemplates the formation of water insoluble soaps of polycarboxylic and monocarboxylic acids in a form and condition rendering them usable together for grease making, but in a manner such that chemically the two soaps retain in the soap product their individual identities, but physically they are so associated as to render the composite fully miscible and compatible with oil to make high quality grease.

Briefly, the invention contemplates making a water insoluble, oil miscible soap composite derived from a polycarboxylic acid component (i.e. one or a mixture of polycarboxylic acids or water soluble soaps thereof), and a monocarboxylic 8 to 22 carbon atom component (i.e. one or a mixture of monocarboxylic acids or water soluble soaps thereof), formed by precipitating a first water insoluble soap of one of the components, as from a solution of an alkali metal soap thereof, and precipitating directly on the soap so formed a second water insoluble soap of the other acid component, as from a solution of an alkali metal soap thereof. As will appear, the precipitated water insoluble soaps may be of the same or different metals. Also, while preferably the polycarboxylic acid soap is precipitated on the monocarboxylic acid soap, the relation may be reversed.

The invention contemplates the use of any or mixtures of the usual polycarboxylic acids (and their soaps) derived e.g. from the heat polymerization or dimerization of fatty acids such as linseed, soy bean, cotton seed and octadecadienoic acids. These dimers have about 36 carbon atoms. Specific acids include sebacic acid, and

25,399,389 Patented Aug. 11, 1959 the dimers of linoleic acid, adipic acid, pimelic acid, azelaic acid and suberic acid.

Usable monocarboxylic acids, saturated and unsaturated and having between 8 to 22 carbon atoms, include stearic acid, fish oil acids and 2-ethyl hexoic acid.

The metals usable and reactable with the acid components in accordance with the invention to form water insoluble soaps, include aluminum, calcium, zinc, magnesium, barium, lead and lithium. These may be reacted in their water soluble forms or compounds such as their chlorides and sulfates. For purposes of definition herein, including the claims, lithium is intended to be excluded from the alkali metals because of its property, unlike sodium and potassium, of forming water insoluble soaps of the saponifiable acids herein contemplated.

In considering the process employed to precipitate the soaps one directly upon the other, assume first that the soaps both are to be precipitated by ions of the same metal and typically that a dimer soap is to be precipitated on a monomer soap in a ratio that ordinarily will be from about 1% to 20% of the dimer soap to the total composite soap. I may first saponify the monocarboxylic acid component with alkali metal hydroxide and separately saponify similarly the dimer acid component. To the monomer soap solution is added a water solution of the chloride or sulfate of one of the named polyvalent metals, e.g. aluminum, in one amount stoichiometrically suflicient to replace the alkali metal content of both the monomer and dimer soaps. Thus is formed a first precipitate of the polyvalent metal monomer soap in aqueous solution containing excess polyvalent metal ions. To the mixture there is added the alkali metal dimer soap solution and with active agitation, the polyvalent dimer acid soap is precipitated and deposited directly on the previously formed polyvalent metal monomer soap. After completion of the reaction, the composite precipitate is filtered, washed and ground to suitable fineness. Generally, the initial saponifications and replacement reactions will take place at solution temperatures between about -170 F.

Where it may be desired to precipitate the soap of two polyvalent metals one upon the other, I may (1) form an alkali metal soap solution of either of the acids, monomer or dimer; (2) then precipitate the soap by reaction with a stoichiometrically equivalent quantity of polyvalent metal ion as derived for example from dissolved chloride or sulfate of the metal; (3) add to the aqueous precipitate mixture a solution of the alkali metal soap of the second acid and (4) under active agitation precipitate on the first formed polyvalent metal soap another soap formed and precipitated by reaction of the second alkali metal soap with a stoichiometrically equivalent amount of a different polyvalent metal derived e.g. from introduction of its chloride or sulfate to the mixture. Thus, in this manner, I may first form the calcium soap of a monocarboxylic acid and precipitate thereon the aluminum soap of a dicarboxylic acid. Similarly, monomer and dimer soaps of any combination of the above named polyvalent metals may be precipitate one upon the other.

Also, it is contemplated that mixed polyvalent metal soaps of the monomer and dimer acids may be formed to have precipitated thereon either a single polyvalent metal soap component, or mixed polyvalent metal soaps, or that such mixed soaps may be precipitated on a single polyvalent metal soap. Thus, the sodium soap of the monomer acid component may be precipitated by reaction with mixed soluble polyvalent metal salts, or a.

single polyvalent metal salt, and the sodium soap of the other acid component precipitated thereof by reaction with single or mixed soluble polyvalent metal salts.

Example 1 800 pounds of fish 'stearic acid and '9 pounds of 2-ethyl hexoic acid (together constituting the monomeric acid component) are saponified to form the sodium soaps :by admixture and agitation with 176 pounds of caustic soda at a temperature of about 1'55160 F.

To the resulting soap solution (batch 1) is added '502 pounds of aluminum sulfate, which with agitation in about the same temperature range precipitates the aluminum soap of the acids.

.20 pounds of dimer acid (Emery Dimer 95 5-dimerized 'linoleic acid) is separately saponified with -4 pounds of caustic soda in solution to form the sodium dimer soap (batch 2).

Batch 2 is then pumped into and agitated with batch l, to cause formation and precipitation of the aluminum dimer soap on the previously formed aluminum monomer soap.

The composite soap precipitate is filtered, water washed, dried and ground to suitable fineness.

Example 2 About 800 pounds of stearic acid is saponified with 176 .pounds of caustic soda to produce the monomer sodium soap as batch 1. About 20 pounds of dimer acid (e.g. Emery Dimer 955) is mixed with 4 pounds of caustic soda in aqueous solution to form the sodium dirnerate soap. To this solution is added 7 /2 pounds-of calcium chloride in 80% solution to precipitate the water insoluble calcium dimer soap.

The precipitated calcium dirnerate slurry is pumped into batch 1, and about 480 pounds of aluminum sulfate in water solution is added and agitated to precipitate the aluminum monomer soap in the calcium dimer soap.

.In grease manufacture, any of the described composite monomer and dimer soaps may be compounded with hydrocarbon acids by the usual procedures, generally by blending 5 to 10% (weight) of the composite soap with a heavy lubricating oil stock (e.g. S.-A.E. 60), the soap being first cold blended with about one-half the oil, the remainder of the oil being added during heating and agitation of the mixture at around 300 F.

I claim:

1. 'An oil miscible, water insoluble soap composition derived from a polycarboxylic acid component and a monocarboxylic 8 to 22 carbon atom acid component, formed by precipitating a first water insoluble metal soap of one of said components from an aqueous solution of an alkali metal soap thereof, and precipitating directly on the soap so formed a second water insoluble metal soap of the other acid component from an aqueous solution of an alkali .metal soap thereof, the precipitated polycarboxylic soap being between about 1% to of the combined precipitated soaps.

2. A soap composition as defined by claim 1, in which said first and second soaps are salts of the same polyvalent metal.

3. A soap composition as defined by claim 1, in which said first and second soaps are aluminum soaps.

4. A soap composition as defined by claim 1, in which said first and second soaps are salts of different metals.

5. A soap composition as defined by claim '1, in which the polycarboxylic acid soap is precipitated on the monocarboxylic acid soap.

'6. An -oil miscible, water insoluble soap composition derived from a polycarboxylic acid component and a monocarboxylic 8 to 22 carbon atom acid component, made by forming a first alkali metal aqueous soap solution of one of said components and replacing the alkali metal with a polyvalent metal to precipitate the water insoluble soap thereof, forming a second alkali metal aqueous soap solution of the other of said components, combining said solutions, and replacing the alkali metal of the soap in the second solution with a polyvalent metal and precipitating the waterinsoluble soap thereof directly on the firstmentioned water insoluble metal soap, the precipitated polycarboxylic soap being between about 1% to 20% of the combined precipitated soaps.

7. A soap as defined byclaim 6, in which the first mentioned water insoluble soap is precipitated by reaction with a portion of a water soluble compound of the first mentioned polyvalent metal dissolved in said first solution, and said second polyvalent metal soap is precipitated by a remaining portion of said compound.

8. A soap as defined by claim 6, in which the polycarboxylic acid soap is precipitated on the monocarboxylic acid soap.

9. The. process of forming an oil miscible, water in? soluble soap composition derived from a polycarboxylic acid component and a monocarboxylic 8 to 22carbon atom acid component, that includes precipitating a. first polyvalent metal soap of one of said components from an aqueous solution .of an alkaline metal soap thereof, and precipitating directly on the polyvalent metal soap so formed a second polyvalent metal soap of the other acid component from an aqueous solution of an alkali metal soap thereof.

'10. The process .of forming an oil miscible, water insoluble soap composition derived from a polycarboxylic acid component and a monocarboxylic 8 to 22 carbon atom acid component, that includes precipitating a first polyvalent'metal soap of one of said components from an aqueous solution of an alkali metal soap thereof,

forming a second alkali metal aqueous soap solution of the other of said components, combining said solutions, and precipitating the last mentioned alkali soap as a polyvalent metal soap-directly on the first mentioned polyvalent metal soap.

11. The process of forming an oil miscible, water insoluble soap composition derived from a polycarboxylic acid component and a monocarboxylic 8 -to 22 carbon atom acid component, that includes precipitating a first polyvalent metal soap of one of said components from an aqueous solution of an alkali metal soap thereof by reacting the alkali metal soap with aportion of dissolved polyvalent metal ions, forming a second alkali metal aqueous soap solution of the other of said components, combining said solutions, and reacting the last mentioned alkali metal soap with a remaining portion of said dissolved .polyvalent metal ions to precipitate the soap of said second solution directly on the first mentioned polyvalent metal soap.

References Cited in the file of this patent UNITED STATES PATENTS 2,555,104 Ashley et al. May 29, 1951 2,583,607 Sirianni et al. Jan. 29, 1952 2,626,897 Young et al. Jan. 27, 1953 2,699,428 Lux etial. Ian. 11, 1955 

1. AN OIL MISCIBLE, WATER INSOLUBLE SOAP COMPOSITION DERIVED FROM A POLYCARBOXYLIC ACID COMPONENT AND A MONOCARBOXYLIC 8 TO 22 CARBON ATOM ACID COMPONENT FORMED BY PRECIPITATING A FIRST WATER INSOLUBLE METAL SOAP OF ONE OF SAID COMPONENTS FROM AN AQUEOUS SOLUTION OF AN ALKALI METAL SOAP THEREOF, AND PRECIPITATING DIRECTLY ON THE SOAP SO FORMED A SECOND WATER INSOLUBLE METAL SOAP OF THE OTHER ACID COMPONENT FROM AN AQUEOUS SOLUTION OF AN ALKALI METAL SOAP THEREOF, THE PRECIPITATED POLYCARBOXYLIC SOAP BEING BETWEEN ABOUT 1% TO 20% OF THE COMBINED PRECIPITATED SOAPS. 